Rotting can occur when cotton is stuffed in the tooth. Usually, during the root canal disinfection step of root canal treatment, small cotton balls are placed in the tooth, combined with temporary sealing material to temporarily seal the root canal, and the small cotton balls and temporary sealing material should be removed after 1~2 weeks, as follows. Root canals need to be sterilized prior to root canal filling to remove microorganisms and toxins remaining in the microstructure. After placing the sterilizing medication into the root canal, the cavity needs to be temporarily sealed. A small cotton ball can be placed at the bottom of the pulp chamber and the temporary sealing material can be pressed into the socket in small increments. The cotton ball helps to isolate the medication from the temporary sealing material. The cotton ball and the temporary sealing material should be removed after 1 to 2 weeks because the temporary sealing material has limited strength and may crumble and disintegrate with prolonged use. Bacteria from the oral cavity may enter the medullary cavity and the cotton ball may rot. It is recommended to visit a regular medical institution to receive professional treatment.